Many people use mobile stations, such as cell phones and personal digital assistants (PDAs), to communicate with cellular wireless networks. These mobile stations and networks typically communicate with each other over a radio frequency (RF) air interface according to a wireless communication protocol such as Code Division Multiple Access (CDMA), perhaps in conformance with one or more industry specifications such as IS-95 and IS-2000. Wireless networks that operate according to these specifications are often referred to as “1xRTT networks” (or “1x networks” for short), which stands for “Single Carrier Radio Transmission Technology.” These networks typically provide communication services such as voice, Short Message Service (SMS) messaging, and packet-data connectivity.
Recently, service providers have introduced mobile stations and wireless networks that communicate using a protocol known as EV-DO, which stands for “Evolution Data Optimized.” EV-DO networks, operating in conformance with industry specification IS-856, provide high rate packet-data service (including Voice over IP (VoIP) service) to mobile stations using a combination of time-division multiplexing (TDM) on the forward link (from the network to mobile stations) and CDMA technology on the reverse link (from mobile stations to the network). Furthermore, some mobile stations, known as hybrid mobile stations or hybrid wireless access terminals, can communicate with both 1x networks and EV-DO networks.
In a wireless network (also referred to interchangeably as a “wireless access network” or “access network”), a traffic channel assignment (TCA) message is used to notify an access terminal of the traffic channel that is assigned to the access terminal. Thus, when an access terminal attempts to establish a connection to an access network, the access network may select a traffic channel for the access terminal, and send the access terminal a TCA message that identifies the selected traffic channel.
Furthermore, the TCA message identifying the selected traffic channel may be transmitted in multiple sectors. By sending the TCA message in multiple sectors of the access network (i.e. sending the message from multiple base stations or radio network controllers), an access network may increase the likelihood that an access terminal successfully receives the TCA message. For example, access terminals operating under EV-DO are configured to periodically transmit a route update message, which identifies sectors as potential handoff candidates, and specifies the pilot-signal strength of those sectors. Accordingly, the TCA message may be transmitted in the access terminal's serving sector, as well as the sectors reported in the route update message.